Assessment of susceptibility of deployed RA receivers operating in 4200-4400 MHz, while taking into account any civil aviation initiatives on improving RA receivers, in order to study the following compatibility scenarios:

1) Unwanted emissions from MFCN operating in 3400-3800 MHz and WBB LMP operating in 3800-4200 MHz into 4200-4400 MHz radio altimeters band

2) Impact of blocking of radio altimeters from 3400-3800 MHz MFCN in-band emissions and from 3800-4200 MHz WBB LMP in-band emissions

Note: the results of this study could trigger further actions as appropriate from ECC or other entities.

Provide relevant long term MFCN operational parameters in 3.4-3.8 GHz for the development of future MOPs by RTCA/EUROCAE for resilient radio altimeters.

It is recognised that realistic scenarios and parameters for RA and MFCN AAS parameters are needed before compatibility studies can be commenced.

Based on the results of the study, consider the need for possible future steps, e.g. improvement of RA susceptibility to interference, in particular regarding blocking characteristics.

It is to be noted that radio altimeters are used globally and once installed they are used over many years. Therefore, development of future MOPS(Minimum Operational Performance Standards) for RA should be forward-looking as well as considering the various 5G MFCN deployments already existing in frequency bands both below 4.2 GHz as well as above 4.4 GHz, in both Europe and globally.